Abstract: The embryo of graben-horst-like tectonic framework of Junggar Basin was originaly formed by an uplift of upper mantle during the time of the early-middle Carboniferous followed by a tension fault of the transitional basement for Devonian and Carboniferous systems. Its Permian, the stage of preliminary development of the basin, was down-faulted developing period. A period of fault/seg and depression occurred in Mesozoic with a continuous subsidence. Finally, after contractive uplift in Miocene ,Present Junggar Basin was formed in the end.

Key words: Junggar Basin, Formation, Evolution, Down faulting, Depression